Electromigration resistant and profile consistent contact arrays

Abstract

A package assembly includes a substrate and at least a first die having a first contact array and a second contact array. First and second via assemblies are respectively coupled with the first and second contact arrays. Each of the first and second via assemblies includes a base pad, a cap assembly, and a via therebetween. One or more of the cap assembly or the via includes an electromigration resistant material to isolate each of the base pad and the cap assembly. Each first cap assembly and via of the first via assemblies has a first assembly profile less than a second assembly profile of each second cap assembly and via of the second via assemblies. The first and second cap assemblies have a common applied thickness in an application configuration. The first and second cap assemblies have a thickness variation of ten microns or less in a reflowed configuration.

What is claimed is: 
     
       1. A composite device assembly comprising:
 a plurality of dies, each die of the plurality of dies includes a respective array of contacts; 
 a substrate extending from a first substrate end to a second substrate end, the plurality of dies are coupled along the substrate, the substrate includes:
 one or more embedded multi-die interconnect bridges (EMIB) having associated conductive traces, the one or more EMIB configured to interconnect the plurality of dies; and 
 a plurality of via assemblies; and 
 each via assembly of the plurality of via assemblies is interposed between the array of contacts of a die of the plurality of dies and the conductive traces of an EMIB of the one or more EMIB, each via assembly includes:
 a base pad in communication with a conductive trace of the EMIB, the base pad includes at least a first conductive material; 
 a cap in communication with a contact of the first array of contacts, the cap includes at least a second conductive material different from the first conductive material; and 
 an electromigration resistant via having a third conductive material different from the first and second conductive materials, the electromigration resistant via is configured to isolate each of the base pad and the cap from intermetallic compound growth. 
 
 
 
     
     
       2. The composite device assembly of  claim 1 , wherein the electromigration resistant via includes nickel. 
     
     
       3. The composite device assembly of  claim 2 , wherein the electromigration resistant via including nickel includes a nickel alloy having one or more of tungsten molybdenum or ruthenium. 
     
     
       4. The composite device assembly of  claim 1 , wherein the electromigration resistant via includes cobalt. 
     
     
       5. The composite device assembly of  claim 1 , wherein the electromigration resistant via includes iron. 
     
     
       6. The composite device assembly of  claim 1 , wherein the electromigration resistant via includes one or more of a cobalt alloy or an iron alloy. 
     
     
       7. The composite device assembly of  claim 1 , wherein the cap includes a solder cap layer and an electromigration resistant cap layer interposed between the solder cap layer and the electromigration resistant via. 
     
     
       8. The composite device assembly of  claim 1 , wherein the cap and base pad include first and second volumes of the respective first and second conductive materials, and the electromigration resistant via includes a third volume of the third conductive material greater than the first or second volumes. 
     
     
       9. The composite device assembly of  claim 1 , wherein the plurality of dies includes a first die having a fine pitch array of contacts and a second die having a coarse pitch array of contacts with a greater contact pitch than the fine pitch array of contacts; and
 wherein the one or more EMIB includes a first EMIB and a second EMIB. 
 
     
     
       10. The composite device assembly of  claim 9 , wherein the plurality of via assemblies comprises:
 a first via assembly array of the plurality of via assemblies, the first via assembly array having a fine via pitch; and 
 a second via assembly array of the plurality of via assemblies, the second via assembly array having a coarse via pitch. 
 
     
     
       11. The composite device assembly of  claim 10 , wherein small profile caps of the first via assembly array and large profile caps of the second via assembly array have a thickness variation of ten microns or less. 
     
     
       12. The composite device assembly of  claim 11 , wherein the thickness variation is 5 microns or less. 
     
     
       13. A composite device assembly comprising:
 a plurality of dies, each die of the plurality of dies includes a respective array of contacts; 
 a substrate extending from a first substrate end to a second substrate end; 
 the substrate includes one or more embedded multi-die interconnect bridges (EMIB) having associated conductive traces; 
 first and second via assemblies coupled between the respective arrays of contacts and the conductive traces of the one or more EMIB, and each of the first and second via assemblies includes:
 a base pad including at least a first conductive material; 
 a cap assembly including at least a second conductive material; 
 a via interposed between the cap assembly and the base pad, and one or more of the cap assembly or the via includes an electromigration resistant material configured to isolate each of the base pad and the cap assembly from intermetallic compound growth; and 
 wherein each cap assembly and via of the first via assembly has a first assembly profile less than a second assembly profile of the cap assembly and via of the second via assembly, and the first and second cap assemblies include application and reflowed configurations:
 in the application configuration the first and second cap assemblies have a common applied thickness; and 
 in the reflowed configuration the first and second cap assemblies have a thickness variation of ten microns or less. 
 
 
 
     
     
       14. The composite device assembly of  claim 13 , wherein the thickness variation is 5 microns or less. 
     
     
       15. The composite device assembly of  claim 13 , wherein the thickness variation is 3 micron or less. 
     
     
       16. The composite device assembly of  claim 13 , wherein the first assembly profile of the first cap assembly and via is a first diameter of around 23 microns or less and the second assembly profile of the second cap assembly and via is a second diameter of around 70 microns or less. 
     
     
       17. The composite device assembly of  claim 13 , wherein the first assembly profile of the first cap assembly and via is a first diameter of around 6 microns or less and the second assembly profile of the second cap assembly and via is a second diameter of around 45 microns or less. 
     
     
       18. The composite device assembly of  claim 13 , wherein the vias of the first and second via assemblies include the electromigration resistant material. 
     
     
       19. The composite device assembly of  claim 13 , wherein the first and second cap assemblies include an electromigration resistant cap layer of the electromigration resistant material between a solder cap layer and a via apex of the via. 
     
     
       20. The composite device assembly of  claim 13 , wherein the via includes nickel. 
     
     
       21. The composite device assembly of  claim 20 , wherein the via including nickel includes a nickel alloy having one or more of tungsten, molybdenum or ruthenium. 
     
     
       22. The composite device assembly of  claim 13 , wherein the via includes cobalt. 
     
     
       23. The composite device assembly of  claim 13 , wherein the via includes iron. 
     
     
       24. The composite device assembly of  claim 13 , wherein the via includes one or more of a cobalt alloy or an iron alloy.